dc.contributorPiquini, Paulo Cesar
dc.contributorhttp://lattes.cnpq.br/4496249071363237
dc.contributorCalegari, Eleonir João
dc.contributorSantos, Cláudia Lange dos
dc.contributorKöhler, Mateus Henrique
dc.creatorGonzalez, Uger Alfonso Herrera
dc.date.accessioned2021-06-02T23:14:03Z
dc.date.accessioned2022-10-07T23:48:53Z
dc.date.available2021-06-02T23:14:03Z
dc.date.available2022-10-07T23:48:53Z
dc.date.created2021-06-02T23:14:03Z
dc.date.issued2020-09-15
dc.identifierhttp://repositorio.ufsm.br/handle/1/21057
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/4041703
dc.description.abstractIn this work we present the results of a methodology that combines first-principle Density Functional Theory calculations with the Green’s functions method in order to treat strongly correlated electronic systems. The material system selected for this study was the La2CuO4. Taking into account that superconductivity in cuprates occurs mainly at the CuO2 planes, only the electronic bands at these planes have been considered. Firstly the electronic levels were calculated in a dense grid of points on the CuO2 planes through the Density Functional Theory. We then used the Green’s functions method, within the one-band Hubbard model with repulsive interaction to include the electronic correlation. The correlated bands were calculated for an occupation number of nT = 0.85 and different values of the Coulomb interaction U . Further, the correlated bands were also obtained for a U value of 1.6 eV, and various occupation numbers nT . The following quantities have also been calculated: density of states, spectral function, specific heat, and chemical potential. The specific heat, as a function of temperature, showed a two-peak structure: one associated to spin fluctuations at low temperatures, and another associated to charge fluctuations, for higher temperatures. The maximum of the chemical potential was showed to depend on the Coulomb interaction U . These results were compared with those obtained using the Tight-Binding method in a square lattice, instead of the first principles Density Functional Theory calculations. It results from this comparison that this methodology can be also applied to other strongly correlated systems.
dc.publisherUniversidade Federal de Santa Maria
dc.publisherBrasil
dc.publisherFísica
dc.publisherUFSM
dc.publisherPrograma de Pós-Graduação em Física
dc.publisherCentro de Ciências Naturais e Exatas
dc.rightshttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International
dc.subjectTeoria do funcional da densidade
dc.subjectModelo de Hubbard
dc.subjectCupratos
dc.subjectDensity functional theory
dc.subjectHubbard model
dc.subjectCuprates
dc.titleTeoria do funcional da densidade acoplada ao modelo de Hubbard de uma banda aplicada ao supercondutor La2−xSrxCuO4
dc.typeDissertação


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